Audio Systems: Audio cutout, headphone jack, internal electronics

Question
I plugged a set of headphones into my Pacific PTV7004 TV. The TV speaker sound cut out and was replaced with a low static noise that got louder as I increased the volume. No sound came through the headphones. No sound returns to the TV when I take out the headphones. There is no option in the TV menu to switch between speaker and headphone, and switching of the TV doesn't fix it. What can I do to restore the sound?

Answer
Hi Gordon,

 My familiarity with British consumer televisions isn't the best - we just don't run across allot of them in the US - but there are a few common problems that may apply.

  Inside most headphone jacks is a tiny "contact switch" that provides the electronic logic to mute the speakers when a headphone jack is inserted.   Part 1 of your problem may be that this switch got stuck when you inserted your headphones.

  You can try to buy some "electronics spray cleaner" - a spray liquid also commonly called "Pot cleaner" (pot in this case is short for potentiometer) and give that a try GINGERLY inside the jack.   You may also want to get a can of compressed air to spray in there as well - that is certainly less likely to damage other internal electronics inside the TV than the pot cleaner will.
  If you are feeling handy then you might want to try opening the case and examining the back-side of the jack - but please be careful, there is a great risk of a terrible shock back there, even if it IS unplugged.

 The static sound I'm not too concerned about.  Unless it's excessive, it's probably always been there - you just don't notice because ordinarily the speakers are also playing TV audio at a much louder volume over the static.  With the speakers muted the static becomes much more noticeable.

  There is a slight possibility that you may have damaged the audio electronics circuitry when you inserted the headphone jack, especially if the earthing pin on the electrical plug has been damaged or removed.  If that is the case then there is little you can do (unless you are feeling VERY handy and know your TTL from your CMOS) but to try and return it to the electronics store...

I might also suggest that you try "Cleggsan" or "Peter G Lee", other experts here at allexperts.com.  They might have more familiarity with  the circuit boards on Pacific TVs.

I wish you luck!